In a Phase III clinical trial among patients with newly diagnosed glioblastoma, the addition of Avastin® (bevacizumab) to standard chemoradiation increased side effects and did not improve overall survival. These results were presented at the 2013 Annual Meeting of the American Society of Clinical Oncology (ASCO).
Glioblastoma is a aggressive type of type of brain tumor that occurs mainly in adults. Treatment often involves surgery followed by radiation and chemotherapy with Temodar® (temozolomide). Because survival tends to be poor even with aggressive treatment, researchers continue to evaluate new ways of treating this disease.
Avastin is a targeted therapy that blocks a protein—VEGF—that plays a key role in the development of new blood vessels. This deprives the cancer of nutrients and oxygen and inhibits its growth. Avastin is used for the treatment of selected patients with lung cancer, colorectal cancer, kidney cancer, or glioblastoma. In the case of glioblastoma, it’s used after other treatments have failed.
To evaluate Avastin as part of the initial treatment for glioblastoma, researchers conducted a Phase III clinical trial among 637 newly diagnosed patients. After surgery, patients were treated with chemoradiation (radiation and chemotherapy with Temodar) alone or in combination with Avastin.
- Overall survival was similar in the two study groups. Patients who received chemoradiation plus Avastin survived for a median of 15.7 months, compared with 16.1 months among patients who received chemoradiation alone.
- Progression-free survival (survival without a worsening of the cancer) was better in the chemoradiation plus Avastin group (10.7 months versus 7.3 months in the group that got chemoradiation alone), but this difference did not meet the criteria for statistical significance, suggesting that it could have occurred by chance alone.
- Side effects that were more common in the Avastin group included low platelet counts, blood clots, and high blood pressure.
In summary, among patients with newly diagnosed glioblastoma, the addition of Avastin to chemoradiation increased side effects without improving survival. These results suggest that Avastin should not be used for the first-line treatment of glioblastoma.
Reference: Gilbert MR, Dignam J, Won M et al. RTOG 0825: Phase III double-blind placebo-controlled trial evaluating bevacizumab (Bev) in patients (Pts) with newly diagnosed glioblastoma (GBM). Presented at the 49th Annual Meeting of the American Society of Clinical Oncology. May 31-June 4, 2013; Chicago, IL. Abstract 1.